BDNF and Stroke: Dose-response exercise research in other populations (e.g., stroke, neurotypical older adults) is mixed regarding whether PA intensity is related to brain-derived neurotrophic factor (BDNF) expression (Boyne et al., 2019; Kovacevic et al., 2020), which is associated with hippocampal neurogenesis (Cotman et al., 2007).